Back in 2004, the city of Philadelphia made news when it decided to create a WiFi network that would blanket the entire city with 802.11b goodness—a 135-square-mile wireless network. At the time, it was the largest planned municipal WiFi deployment to be attempted. The city selected EarthLink to build out the network, and after three weeks of testing in a 15-square-mile area, the city and EarthLink are planning to go ahead and finish blanketing the entire city.

Given the ambitious nature of the Philadelphia network, cities and towns around the world are watching to see if performance lives up to expectations. "All eyes are on that network," wireless broadband consultant Phil Belanger told the Philadelphia Inquirer.

Belanger's consulting company, Novarum, recently ranked the top 10 municipal WiFi networks in terms of performance, and Philadelphia came in second place for performance and fifth place overall. Part of the reason for Philadelphia's solid performance is the number of nodes in the network. EarthLink has as many as 47 nodes per square mile, with an average of 42 nodes.

Early estimates were that 20 to 25 nodes per square mile would do the trick. According to Wi-Fi Net News, municipal WiFi company Tropos has since raised its baseline for nodes per square mile to 30—which EarthLink has deemed insufficient to provide adequate coverage in Philadelphia.

The increased number of nodes seems to have paid off in terms of network performance, as some users have been able to get speeds faster than the 1Mbps officially offered by EarthLink. More extensive testing by the Inquirer led to a mixed bag of results. Their reporters were able to get online via the network 20 of the 35 times they tried, finding that coverage and signal strength could vary significantly block by block.

Philadelphia is offering different tiers of access for its network and hopes to have 12,000 customers signed up by year's end. There's a $6.95 per month introductory rate, which will jump to the standard $21.95 after six months. Low-income residents can get the service for $11. You can also buy access by the hour for $3.95, get a day-long pass for $7.95 and a three-day pass for $15.95. For users that plan on using the municipal network for their home broadband connection, EarthLink recommends getting an additional piece of hardware to ensure a solid signal indoors.

Whether the city of Philadelphia meets its goal of 12,000 subscribers is really irrelevant, argues technology consultant Craig Settles, who also authored Fighting the Good Fight for Municipal Wireless. "If politicians and the media continue to portray use of the networks by consumers and residents as the ultimate measure of success, they're setting the networks up for failure," Settles told Ars.

Settles also believes that the key metric for success of a municipal WiFi network is how efficiently the cities make use of the resource. "Cities should see significant savings from these networks if they use them for internal applications and lowering costs," says Settles. "Philadelphia should be able to stop paying for data services from cellular carriers and cease relying on many external providers."

Cities should also be wary of heavy reliance on consumer use to finance the network, says Settles. "The consumer base is the most fickle, unreliable, and questionable revenue stream," he argues. Instead, cities should focus their efforts on making sure the service is attractive to businesses.

There are close to 400 municipal WiFi installations in the process of being planned or deployed, and the news from Philadelphia appears to be a bit of a mixed bag. The good news is that the networks should work fairly well—as long as the node density is high enough. Settles notes that smaller, less-dense towns will require fewer nodes. But for big cities, more nodes means a more expensive network deployment: those WiFi networks are going to cost significantly more than first thought.

Eric Bangeman
Eric has been using personal computers since 1980 and writing about them at Ars Technica since 2003, where he currently serves as Managing Editor. Twitter@ericbangeman